Sulphonates



Jan. 27, 1970 P. J. GARNER ETAL 3,492,343

SULPHONATES Filed April 20. 1967 O.5vol./

I (Z9 l/ m VO. a E 88- U) 10 vol.%

TIME iN MINUTES.

In venfors Philip James Garner And Howard Nielsen Moulden United StatesPatent US. Cl. 26l 513 8 Claims ABSTRACT OF THE DISCLOSURE The inventionconcerns a process for the purification of olefins from which olefinsulphonates having an improved colour can be obtained. The processinvolves treatment of an olefin, especially a commercial alphaolefin,with sulphuric acid under specific conditions, followed by treatmentwith an earth.

This invention relates to sulphonates of olefins, especially ofcommercial alpha-olefins of carbon chain length 10-22, to a process forpreparing them, and to their use in detergent compositions.

Useful actives for detergent compositions can be prepared by allowing SOto react with olefins of chain lengths ranging from C -C with subsequenthydrolysis/neutralisation to the salt. Unfortunately, in many cases, thesulphonate derived from commercially available alpha-olefins is toohighly coloured to be acceptable for use in finished detergent products.

Commercially available alpha-olefins, especially those which are derivedfrom the cracking of petroleum hydrocarbons, known as cracked waxolefins, tend to be straw coloured and to contain not only colouredimpurities but also compounds which may be colourless in themselves butwhich give rise to highly coloured compounds on reaction with S Theseintensely coloured compounds which appear to be present in thesulphonate product in very small concentrations are thought to bepolysulptonated polyenes, possibly derived by oxidation and subsequentsulphonation of the hydrocarbon chain of some of the more reactiveimpurities. They are believed to account for much of the sulphonatecolour. Conjugated polyenes of the type R(CH=CH),,R are known to behighly coloured when n=6. The coloured compounds obtained in thesulphonation of commercial alpha-olefins are not necessarily linear andmay well be derived from the non-straight chain impurities. They mightalso be formed from olefin dimers or from fragmented olefins, but themajor colour body precursors are believed to be polyenes andparticularly the cyclic dienes.

The situation is complicated by the lack of a simple test by which anyparticular olefinic raw material can be classified as being likely toyield a sulphonate of good (i.e. acceptable) or unacceptable colour indetergent compositions. An olefin feed stock which appears Waterwhitecan, nevertheless, on sulphonation, give a sulphonate of too high acolour. In consequence, the olefin has to be test-sulphonated before itis known if it is suitable for detergent sulphonate production. Suchsulphonation is best carried out on a pilot plant scale asrepresentative of the envisaged large-scale processing. This is atimeconsuming operation and requires large quantities of olefin.

As has been stated above, when the commercial alphaolefins are used toprepare alkali metal sulphonates for use in detergent compositions, thecolour level of these sulphonates is too high. It is therefore necessaryto reduce the colour level of the olefin sulphonates.

Whilst it has been common practice in the detergent industry to improvethe colour of sulphonated hydrocarbons by bleaching, it is not possibleto improve the colour of these sulphonates in many cases, particularlythose of cracked wax olefins. Bleaching, even with unusually largequantities of bleaching agent does not effect the requisite colourimprovement. This has precluded hitherto the use of the cracked waxolefins for detergent sulphonates.

The present invention is concerned with a means for producing acceptablycoloured sulphonates from commercial olefins. In particular, it isconcerned with a means of removing the undesirable colour-formingcompounds from the olefins before sulphonation, so that the finalsulphonate product has an acceptable colour. The invention is applicableto cracked wax olefins as such and is particularly useful therewithsince the combined cost of these olefins and the purification process ofthis invention is much less than the cost of the other commerciallyavailable olefins made from ethylene by a Ziegler polymerisationprocess. The latter type of commercial olefins generally give bettercoloured sulphonates but if the process steps of this invention areemployed some of these Ziegler olefins can be purified thereby.

The cracked wax olefins contain typically -95% straight chainalpha-olefin, the remainder being a mixture of many hydrocarbon types,including branched, cyclic, internal olefins and smaller quantities ofdienes. The Ziegler olefins similarly contain 85-90% straight chainalpha-olefins but the remainder is mainly a mixture of 2-akyl-l-olefins. Whilst the Ziegler olefins are usually water-white,nevertheless on sulphonation, colour can develop, and the product isthen unsuitable for detergent compositions.

It has been proposed to purify the olefins by passing them overabsorbents, such as silicas, aluminas or clays. Washing the olefins withsolvents are also prior proposals. Whilst these methods are recognisedas removing the more polar or the more basic hydrocarbons, they do notalways provide sutficient purification to produce an olefin which issuitable for sulphonation for detergents.

It has also been proposed to improve the visible colour of olefins bytreatment with sulphuric acid. In contrast to the treatment of otherhydrocarbons the conditions for treatment of olefins With sulphuric acidare extremely critical since the olefins themselves react with sulphuricacid. It has also been proposed to purify commercial olefins to renderthem suitable for free radical reaction by way of sulphuric acidtreatment but this prior proposal included very many processing steps,viz, after the contacting of the acid and olefin the mixture is allowedto settle and the acid layer removed. The olefin layer is thenneutralised with base and then washed repeatedly until the water washingis neutral. The washings are necessary to prevent the olefin reactingfurther with entrained acid, to prevent isomerisation and sulphation andto prevent corrosion of equipment in the subsequent steps. After adrying step the olefins are very often re-distilled to remove anycondensed by-products of the treatment and thus to complete theirpurification. Although the olefins so obtained by this prior proposalhave possessed some improved properties, the treatment has oftenresulted in the isomerisation of some of the olefins to internalolefins. For some uses, this isomerisation is undesirable. Consequentlythis purification proposal is not really satisfactory in that itinvolves a plurality of operating steps, and since some of the productsof the acid treatment are highly surface-active emulsions are formedparticularly in the caustic and water Washing stages,

which necessarily cause loss of olefin and give rise to problems ofprocessing and storage.

The present invention, which provides a process for the treatment ofolefins prior to sulphonation to make possible the production of analkali metal sulphonate of a good colour which is suitable for inclusionin a detergent composition, is appreciably simpler than the foregoingproposed process. It completely eliminates the many washing steps andthe distillation step and it does not isomerise the olefin. Indeed, inmany cases, the present process renders unnecessary a bleaching step forthe sulphonates so prepared, and this, as will be apparent to thoseskilled in the art, is a considerable advantage.

Accordingly, the present invention provides a process for thepurification of olefins which comprises subjecting the olefin totreatment with sulphuric acid under conditions which do not give rise toolefin sulphation or isomerisation to yield an acid layer and an olefinlayer, phase separation of the layers and treatment of the olefin layerwith an absorbent.

The treatment with sulphuric acid should be such as to avoid,substantially isomerisation, particularly when alphaolefins are to bepurified since retention of the olefinic double bond in thealpha-position ensures that the sulphonate group adds itself to the endof a long chain, a positioning which is desirable in detergent actives.It should also avoid polymerisation and formation of the esters ofsulphuric acid. By the reaction of the sulphuric acid and thealpha-olefins according to this invention, only 1% at most of highboiling material based on the weight of the starting olefin remains inthe olefin layer at the end of the acid absorbent treatment. The acidtreatment removes the more powerful colour precursors, which arebelieved to be, in the case of the cracked wax olefins, the more basicalkyl-cyclopentadienes, and the open chain conjugated dienes.

It has now been found that sulphation of the olefin should be avoidedbecause the sulphated products which are mainly a mixture of alkylhydrogen sulphate and dialkyl sulphate are detrimental to good colourand also to future processing of the olefin. Some, for example thedialkyl sulphates, cannot be removed from the olefin by water washingsince they are truly soluble in the olefin. A test is described below bywhich acid treatment conditions according to the invention suitable forany given olefin can be established. It will be realised that commercialolefins, especially cracked wax alpha-olefins vary considerably frombatch to batch, as between suppliers, and as between different carbonchain cuts. The significance of the dialkylsulphate formation in thecriticality of the conditions for effective acid treatments of olefinshas not hitherto been appreciated. Use of the test enables any olefin tobe successfully treated by the process of the invention to yieldsatisfactory sulphonates.

The sulphuric acid strength is conveniently 7098% by weight H 80preferably 80-90Z. 86Z is usually the preferred acid strength forreasons which will be given later. It is advantageous that sulphuricacids of this strength are not corrosive to mild steel, a convenientstructural material. The amount used should lie within the ratiosolefinzacid volumes of 100:0.1 to 4:1. It may be convenient to recyclethe acid sludge, in which event, the olefinzacid ratio may be as high as1: 1. The temperature at which the acid treatment is carried out can befrom -100 C. preferably 50 C. provided of course that the temperature isgreater than the freezing points of the acid and the olefin. The time ofcontact is of the order of 0.560 minutes, preferably 220 minutes. Theolefin and acid conveniently are stirred together.

Although the range of acid strength suitable for the treatment can bewide, the combination of acid strength and contact time, quantity ofacid and temperature is critical in order to confine the reaction to thecompounds which cause high sulphonate colour in the crude olefin, and oavoid xcessive occurrence of r action of the a phaolefins themselves.When the stronger acids are used, short contact times, lower temperatureand smaller quantities of acid are needed to avoid occurrence ofsulphation and isomerisation. On the other hand, the weaker acids needlonger contact times and higher temperatures, together with a largerratio of acidzolefin, to enable suflicient reaction with the undesirableimpurities to occur.

The above referred-to test will now be described. A selected quantity ofthe olefin to be purified is treated with sulphuric acid of strengthlying within the range 93% H 50 (w./w.) at concentrations of 0.5 to 10vol. percent for a time of up to 50 minutes. The mixture is allowed tophase separate and the resulting olefin layer is subjected to astandardised earth treatment, viz, l 6% type 237 fullers earth is mixedwith the olefin layer for 8 minutes with settlement for the necessaryperiod for clarity. The infra red spectrum of the resulting olefin isthen recorded, the absorbance being measured at 6.25 and 8.4 to providea measure of sulphation, and at 10.1 and 10.4a to provide a measure ofolefin isomerisation.

For olefins suitable for detergent sulphonates, the acid treatingconditions should be such that the ratio of absorbance at 8.4; to thatat 6.25 is preferably zero but in any case no greater than 0.25, and toavoid olefin isomerisation, the acid treating conditions should notallow the ratio of absorbances at 10.4 to 10.1/L to be greater than thatin the starting olefin. When the ratio of absorbance at 8.4 to that at6.25;. lies between 0.15 and 0.25, colour improvement is effected, butthe final detergent sulphonate product may contain an unduly largeamount of nondetergent organic matter. In this case, it may be necessaryto remove this by, for example, solvent extraction in order to produce aproduct satisfactory for detergent use.

As an illustrative example a cracked wax C1548 olefin (ex ChevronChemical Co.) was acid treated using different values for acid strength,quantity and contact time and the resulting olefin layer subjected tothe standardised earth treatment of the test.

The curves in the accompanying figure graphically present the results;all conditions of acid treatment lying beneath the respective curvesrepresent treatments which yield a sulphonate which is satisfactory foruse in detergent compositions. The areas beneath each of the respectivecurves represent the optimum conditions, ie at which no sulphation orisomerisation occurred or, expressed in another way where absorbance at8.4a was zero, and at 10.4 microns identical with that of the startingolefin.

Conditions represented by points above the respective curves spoil theolefin from the point of view of produc ing acceptably coloured olefinsulphonates. They also result in handling difficulties and yield lossesin the adsorbent treating stage as described later.

It will be appreciated that the curves in the figure do not necessarilyapply to any other batch of olefins even to a nominally identical batchwhose identity is supported by examination by infra red analysis and bygas chromatography. As a practical measure, therefore, it is preferableto employ acid treatment conditions which are represented by pointsslightly below the 10 vol. percent curve when using 3 vol. percent of86% acid. These are generally applicable successfully and give rise tono problems of sulphation, isomerisation or processing.

The criticality of the acid treatment of course, arises from the factthat sulphuric acid of strength sufiicient to bring about a purificationis strong enough to cause sulphation of the olefin itself. 86% sulphuricacid is a convenient acid for the treatment. It is strong enough toeffect a purification yet not so reactive as to require a very shortcontact time.

The manner of mixing of the olefin and of the acid is relativelyimmaterial, provided that good contacting is obtained.

The product resulting from the acid treatment is a mix ture of twophases viz. a lower dark coloured acid layer, and an upper red olefinlayer. When the acid treatment is carried out as recommended so thatlittle or no sulphation as evidenced by the 8.4 micron absorbance ratiooccurs, the mixture readily separates in the subsequent settling stage.If however, undue sulphation has been allowed to take place, the acidlayer does not settle so readily and sulphation continues to occur inthe settling stage. This causes difiiculties in the acid removal stepand eventual olefin spoilage. The two phases are separated as cleanly aspossible, for example by centrifuging and the olefin layer isimmediately treated with an adsorbent preferably in absence ofatmospheric moisture. This olefin layer is neutral and requires notreatment prior to subjection to the adsorbent. The sludge layer can berecycled for acid treatment of fresh olefin. The two treatments i.e.acid followed by adsorbent can be carried out directly, i.e.sequentially Without an intermediate step such as a washing step.Suitable adsorbents are fullers earths, Celites (registered trademark)activated charcoal, clays or a claylike material, aluminas, silicas, andaluminosilicates. The amount of adsorbent used is 115%, preferably05-10% by weight of the olefin. The preferred adsorbent is anacidactivated fuller earth, for example that available as Type 237 fromthe Fullers Earth Union Co. Ltd., Redhill, Surrey, with which the amountis preferably 1.36% by Weight. This quantity is disproportionally lessthan is required with other fullers earths, which are in turn, preferredto the remaining above-specified adsorbents. Silica gel, especially thechromatographic grade is also an etficient adsorbent, but has a farshorter life than has a fullers earth as measured by the quantity ofolefin it will treat. The amount of material requiring removal from theolefin layer is of course a factor in determining the amount of earth tobe mixed with the olefin layer. Contact time is of the order of 5-10minutes. The temperature at which the olefin layer and adsorbent aremixed is usually room temperature. Mixing is achieved by any of theusual methods, e.g. mere stirring together for example, for about 5minutes, or percolation of olefin layer through the bed of adsorbent.The mixing need only be mild in nature.

The adsorbent removes the coloured compounds which stay dissolved in theolefin layer and which were formed by the previous treatment of theolefin with sulphuric acid; i.e. it removes the materials which harm theproduct sulphonate and which cannot be removed by purely physicalmethods by settling, centrifuging and which react with water to givecoloured olefin soluble compounds. At the same time, the adsorbentremoves traces of the highly coloured acid layer which may not have beenremoved in the preceding phase separation. The adsorbent treatment canbe applied in one or more stages. The number of stages and the quantityof earth needed to obtain the required olefin quality depends on thequality of the starting olefins. The preferred amounts are 3 l.3% earthor 1X 6%. A one stage treatment has the obvious advantage of lesshandling and filtration. Where olefin is, because of inefficientmechanical separation, remaining on the earth, it can be recoveredtherefrom by simple boiling of the earth in water for a short time.Phase separation subsequently yields 75% olefin recovery. The residualearth maintains sutficient activity to be re-usable although possibly ingreater quantity, for further olefin pre-treatment. The adsorbents maybe removed from the olefinic layer by filtration or sedimentation.Suitable methods are with filter presses, meta filters or solid bowlcentrifuges. The separation will be found to be straightforward, whenthe process of the invention has been employed: If however, a processnot according to the invention has been used, and particularly whensulphation has occurred, the resulting olefin is of poor quality and theadsorbent becomes sticky, extremely difi'icult to filter and forms astable suspension. The olefins resulting from the two stage treatmentwith sulphuric acid and fullers earth have fewer colour formingimpurities and are immediately suitable for sulphona- 6 tion. Causticand water washes are not necessary, neither is distillation required.The two stage treatment is effective to a surprising degree. Not onlydoes it remove most of the colour forming impurities but it also removessome of the visible olefin colour.

Many of the sulphonates derived from olefins treated in this way aresuitable for inclusion directly into detergent products. Others mayrequire a bleaching treatment but in contrast to the sulphonates of theuntreated olefins it is possible to bleach them to an acceptable colourlevel, i.e. the olefins pretreated according to the invention are muchmore amenable to bleaching treatment.

The process according to the invention may of course be applied on acontinuous basis. The accompanying figure emphasises the need for shorttimes of mixing the acid and olefins when acids of strength greater than86% are used. When the treatment is required for quantities of olefin ofup to 20 lbs. the control of mixing time presents no problem and theoperation can be carried out batchwise. However, when large quantitiesof olefin are re quired, as for commercial use, batch operations are notfeasible since the time taken to add the reagents to the mixing vesselcan very often be greater than the maximum allowable mixing time. Inlarge vessels it is virtually impossible to avoid mixing during theaddition of the reagents. Continuous operation is thus to be preferredto enable control of mixing time.

The invention is also concerned with the additional step of preparingthe sulphonate from the purified olefins. It is preferred to sulphonateusing dilute S0 gas, e.g. SO air using a film reactor, particularly afalling film reactor, having cooling water at about 20 C. Thesulphonation conditions are selected from an olefin to SO ratio,(expressed in moles) of from 1:0.7 to 1:2, preferably 1:1 to 1:15; areaction temperature of 4080 C., a residence time of olefin in contactwith the SO /air stream of 0.5- 30 seconds, preferably 520 seconds. TheSO /inert gas stream is preferably SO air in concentration SO :air ofall S0 to 1:99, preferably 15:85 to 2:98. When sulphonation is carriedout in a stirred tank reactor, then conditions are usually 2045 C.,5-10% vol. percent in air, 1.0:1 to 1.5 :1 sO zolefin (in moles) and areaction time of 1050 minutes. There are other ways in whichsulphonation of the purified olefins may be achieved, for example,reaction of atomised olefin with a diluted S0 stream.

The invention will now be described by way of examples. In theseexamples the product of sulphonation Was collected and stirred with 5%aqueous sodium hydroxide for 2 hours at C. The product was cooled anddiluted with 50% isopropanol in water to give a solution containing 3.5%active detergent as measured by titration withcetyldimethylbenzylammonium choride. The solution colours were measuredin a cell having a path length of 5%" with a Lovibond t-intometer. Withthis test, Lovibond values of 1.5-2. or less, red, and 7-9 or lessyellow, are deemed to be of satisfactory colour level for inclusion ofthe product in coloured detergent com-positions. For use in whitepowders or in white personal washing tablets. the requirements are farmore stringent, and Lovibond colours of 0.7-0.9 red and 2.53.0 yelloware considered satisfactory. In many of the examples, the improvement incolour of the sulphonate resulting from the process is sufiicient fordirect inclusion of the product into detergent compositions. In otherexamples, althrough the colour of the sulphonate has been improvedsubstantially, bleaching is required to bring the colour levels to thedesired standard.

EXAMPLE 1 Olefins derived from a wax cracking process and which werepredominantly C -C alpha-olefins were fed directly to a falling filmsulphonator reactor 0.81 internal diameter, 8' in height, at a rate of20 lbs/hour together With S0 (8.3 lbs/hour) admixed with dry air, the S0concentration being 4 vol. percent. The residence time was 10 secs. Theresults were as follows:

8 EXAMPLE An experiment in which a 25% activated silica gel treat-Sulphonation Conditions Moles Sulphonato S03 Colour Preper Lovibondtreatmole Temp., Olefin Feed ment olefin C. Red Yellow C15-C20 crackedwax olefins None. g EXAMPLE 2 ment was applied to the olefin againwithout acid treat- 3 litres of the olefins as used in Example 1 weresubjected to pretreatment according to the invention. They were shakenwith 150 rnls. of 86% H 50 for minutes at 25%. The mixture was allowedto settle for 10 minutes and then phase-separated. The upper layer wasmixed with 90 g. of acid-activated fullers earth, and filtered. Thefullers earth treatment was repeated and gave a bright, clear olefinlayer, which amounted to 97% of the starting material. Olefinisomerisation could not be detected from the infrared spectrum byreference to the trans band at 10.4 m The pretreated olefins were thenfed to the sulphonation reactor as described in Example 1. The resultswere as follows, and show the greatly improved colour properties of thesulphonates of Example 2 over those of Example 1.

percent Fullers earth.

EXAMPLE 3 An experiment, similar to that of Example 2, wherein the sameacid treatment was used, repeated 3 times and was followed by a causticwash and a water wash as proposed in the literature gave the followingresults:

Sulphonation Conditions Sulphonate Moles Colour $0 per Lovibond moleTemp, olefin 0. Red Yellow Although these sulphonates are of goodcolour, this process is difiicult and relatively expensive by virtue ofthe many steps involved as discussed above. Here, olefin recoveryfollowing the combined acid, caustic and water treatment was only 88%,in contrast to the 97% recovery from the process according to theinvention used in Example 2.

EXAMPLE 4 An experiment in which a 4% fullers earth treatment wasapplied to the olefins, without the acid treatment gave the followingresults, on sulphonation according to Example 1.

Sulphonation Conditions Sulphonate Moles olour $03 per Lovibond moleTemp, olefin C. Red Yellow merit gave the following results onsulphonation according to Example 1.

SO /olefin Red Yellow Untreated (31 -01 olefins 1. 25 6 40 S102 treatedI 4 lbs. of olefin per lb. 810; 1. 25 5 12 l BDH chromatographic Grade.

Thus the combined sulphuric acid-fullers earth treatment is superior totreatments with the individual agents by themselves and indeed superiorto treatment with much larger quantities of a far more powerfuladsorbent by itself. Poor olefin recoveries result from the sulphuricacid treatment, while fullers earth alone did not give sulphonates ofacceptable colour.

EXAMPLES 69 The efficiency of the process according to the invention isfurther demonstrated by the following typical examples.

EXAMPLE 6 C 1 cracked wax alpha-olefins light yellow-green in colourwere treated with 5 vol. percent H (86%) and stirred for A hour. Aftersettling for hour the acid was run ofr and the olefin layer was treatedwith 3 X 1.3 earth (Type 237) with filtration between each earthtreatment. Sulphonation using an 8 x 0.81" internal diameter fallingfilm reactor at 20 lbs. olefin throughput/ hour with a cooling watertemperature around 21 C. was used. The residence time is approximately10 seconds. The results are as follows:

S0 Lovibond alpha Percent conole version Red Yellow EXAMPLE 7 Using theprocess as described in Example 6 but with increase of the throughput to25 lbs. olefin per hour, the results were as follows:

Using the process as described in Example 6, but with were as follows:

10 now free of red colour, clear and non-acidic was sulphonated asdescribed in Example 6. Where the olefin leaving the settler containedan undesirably large quantity 3?; Percent com Lovibmd of suspended acidsludge this was removed by passing olefin version Red Yellow 5 through apad of glass wool to coalesce the acid. Untreated L 64 26 130 Thepurified olefin was then sulphonated in the reactor Tfefitednun ri E am1 l und the listed SO concentra- Untreated." 1. 25 80.4 3.0 14.1 bed m Xe 3 Treated 1.25 78.8 1.4 5.2 tions and conversions. It will be notedthat very h1gh ggg g if 25-3 $8 conversions (i.e. percent olefinreacted) were successfully gritreatedn 1.5 95-3 3.3 ii-8 10 used. TheLovibond values are again for the unbleached 9 sodium sulphonate.

CONTINUOUS ACID TREATING OF Orr-Ctr CHEVRON ALPHA-OLEFINS Acidtreatment/Earth treatment 1.4 moles S03 1.25 moles S03 Sulphonatesulphonate Acid Res. Res. 8. 1:6.25 10.41101 Colour Colour Strength,Acid Time Time Micron Micron (Lovibond) (Lovlbond) Wt., Vol., Reactor,Settler, Absorbance Absorbance Conversion, m Conversion, Run PercentPercent minutes minutes Ratio Ratio Percent Red Yellow Percent RedYellow 86 3.0 41 0.11 0. 02 99.2 3.4 12.7 93.5 2.1 10.5 86 3.0 2 8.50.00 0. 02 99.0 3.9 13.7 93.5 3.6 13.2 90 0.5 1.2 2.2 99.6 2.1 9.1 9.573.5 14.1 90 0.5 1.2 2.2 500 8.4 18.6 97.9 3.2 12.3 86 3.0 2.1 6.6 90.32.8 11.4 1.4 8.1 85 3.0 2.1 6.6 99.4 3.5 13.2 94.2 2.0 12.0 84 3.0 2.10.6 100 3.2 12.1 94.1 1.6 23.4 86 3.0 2.1 6.0 100 4.1 23.0 94.5 1.6 9.9None 98. 0 s. 4 25. 7 89. 7 6. 6 23. 4

EXAMPLE 9 The olefins from these acid treatments/earth treatments C1548cracked wax olefins were treated with 3 vol. percent H SO (86%) andstirred for 3-5 mins. After 10 mins. settlement the olefin layer wastreated with IX 6% (Type 237 fullers earth) and sulphonated under theconditions of Example 6.

S0 Lovibond alpha Percent conolefin version Red Yellow Untreated 1. 065. 5 6. 1 45. 0 Treated l. 0 67 1. 6 7. l Untreated 1. 4 65. 8 6. 2 40.0 Treated 1. 4 93. 5 2. 5 l2. 0

EXAMPLES 10-17 The following table gives the results of experiments onthe application of the invention to continuous operation. In these, theolefins and sulphuric acid were pumped separately to a small stirredtank reactor using the conditions specified in the table below. Themixture was allowed to overflow to a settling vessel where phaseseparation of the acid and olefin layer took place. The acid was run offfrom the bottom of the settler and the olefin was treatedsemi-continuously with fullers earth Type 237. This operation wascarried out by allowing the olefin to overflow from the settler to astirred tank containing a prescribed quantity of the earth. Whensufficient olefin had been added to provide a 6% concentration of earth,the olefin from the settler was passed to a second earth treating tank.The earth was removed from the olefinearth slurry using a metafilter andthe olefin which was contain little or no di-alkyl sulphate and no moreinternal olefin than was in the olefin before treatment, as judged byinfra-red analysis. The foregoing results clearly demonstrate theimprovement in sulphonate colour obtained by the pretreatment of theolefins according to the invention. It will be understood that althoughsome of the colour levels of the treated olefins lie outside the limitsexpressed as suitable for detergent products, the sulphonates of thetreated olefins may be bleached readily, so as to bring the colourlevels within the specified range.

EXAMPLE 18 The improved bleachability of sulphonates of pretreatedolefins will now be illustrated by way of Example 18. This shows thatthe sulphonates from pretreated olefins can be bleached to a lightercolour than can the sulphonates of the untreated olefin, and that lessbleaching agent is required for this operation. A 30% active detergentslurry of the neutralised and hydrolysed sulphonate product obtained asdescribed above, was heated on a steam bath to 70 C. and sodiumhypochlorite bleach added in sufficient quantity to provide aconcentration listed in the table below. The temperature was maintainedfor 30 minutes and then the mixture allowed to cool before measuring thecolour.

Before Bleaching After Bleaching Percent Red Yellow bleach 1 Red YellowUntreated 7 28 g Z 3 1. 0 3. 8

Treated3 vol. percent 86% H 804. 15 mins., 1 0.9 2. 4 3 x 1.3 wt.percent type 2. 5 13 2 0.9 2. 1 237 Fuller's Earth. 3 0. 9 1. 6

1 Measured as wt. of available chlorine per wt. units of active detergent, the active detergent being measured by titration withcetyldimethylbenzylammonium chloride.

1 1 quent bleaching, r sulphonation of random olefins, which have beentreated with acid followed by caustic and water Washing anddistillation.

We claim:

1. In a process for the manufacture of alpha-olefin sulphon'ates, theimprovement yielding an alpha-olefin sulphonate with acceptable colorfor use in a detergent composition which comprises treating analpha-olefin with from about 2% to about 7% by volume of sulfuric acidhaving an acid strength of about 85% to about 87% by weight of sulfuricacid for about 2 to about minutes so as to avoid sulphation andisomerization of said olefins, and to provide an olefin layer and anacid layer, phase separating said olefin layer, treating said olefinlayer with an acid-activated fullers earth, separating the purifiedolefin layer therefrom, and subjecting the resulting olefin tosulphonation and neutralization/ hydrolysis.

2. A process according to claim 1 wherein said acid contactingconditions are 85 87% acid strength (by weight H 80 2-7 vol. percent H50 and 2-10 minutes.

3. A process according to claim 1 wherein said adsorbent is selectedfrom an earth, a clay, activated charcoal and a silicate.

4. A process according to claim 1 in which said earth is present inamount l-1S% by weight of said olefin layer.

5. A process according to claim 1 in which said olefin layer is treatedwith said earth in absence of atmospheric moisture.

6. A process according to claim 1 which includes an additional step oftreating said purified olefin layer with at least one treatment withsaid earth.

7. In a process for the manufacture of alpha-olefin sulphonates in whichan alpha-olefin is reacted with a sulphonating agent, the improvementyielding an alphaolefin sulphonate with acceptable color for use in adetergent composition which comprises the steps of:

(i) contacting with said olefins from about .1% to about 50% by volumeof aqueous sulfuric acid having a concentration of about 70% to about98%, for a period of about .1 to about 60 minutes (ii) allowing saidolefin and sulfuric acid mixture to separate into an acid layer and anolefin layer (iii) treating said olefin layer with an absorbent, and

(iv) separating said absorbent from said olefin (v) said sulfuric acidconcentration, volume percent and contact time with the olefin beingsuch that the ratio of absorbence of an infra-red spectrum of theresulting olefin at 8.4 to that at 625 is no greater than .25 and at10.4,LL to 10.1;1. is no greater than that of the starting olefin.

8. The process of claim 7 wherein the resulting olefin is subjected tosulphonation and neutralization/hydrolysis.

References Cited UNITED STATES PATENTS DELBERT E. GANTZ, PrimaryExaminer I. M. NELSON, Assistant Examiner US. Cl. X.R.

Patent 3.492 .343 Date -AW Invent 1-( Philip James Garner and HowardNeilson Moulden It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 3 line 32 change "absorbent" to --adsorbent--.

Column 3, line 56 change "80-90Z" to --8090%- and change "862" to 86%-.

Column 5, line 68 change to Column 7, line 18, Example 2 change "25%" to-25C.

In the Table entitled "Continuous Acid Treating of C -C ChevronAlpha-Olefins": l5 18 Under heading "1. 4 moles S0 Conversion, Percent"for Run 13 change "500" to --l00-.

Under heading "1. 25 moles S0 Conversion Percent" for Run 12 change"9.57" to --95.7.

Under heading "1.25 moles SO Sulphonate Colour (Lovibond) Yellow" forRun 16 change "2 4" to -9 .4-.

In the Claims:

- Claim 2, line 1 change "Claim 1 to --Claim 7-.

Claim 3 line 1 change "Claim 1" to -Claim 7.

LNGNFD MED 10 Oman- P.

FORM 90-1050 (NJ-69) nrnnnnnn .n

